SUPPLEMENTARY INVESTIGATION AND LABORATORY … SPRINGS...• Presentation of this report providing the results of the subsurface exploration, laboratory testing, and our conclusions

October 31, 2006 Mr. Mark San Agustin Project No. 1208-001-01 Home Land Investments Document No. 06-0912 2239 Curlew Street San Diego, CA 92101 SUBJECT: SUPPLEMENTARY INVESTIGATION AND LABORATORY TESTING

Aggregate Resource Evaluation Proposed Bernand Quarry San Diego County, California

Dear Mr. San Agustin: In accordance with your authorization, we have completed a supplementary geotechnical investigation and laboratory testing for the subject project. This report presents the results of our supplementary geotechnical investigation and the results of laboratory testing for aggregate evaluation.

1 INTRODUCTION This report presents the results of our supplementary geotechnical investigation and laboratory testing for the proposed Bernand Quarry in San Diego County, California. The purpose of our supplementary work was to complete additional laboratory testing in order to further evaluate the aggregate at the site. The conclusions and recommendations presented in this report are based on the subsurface conditions encountered during our field explorations, engineering evaluations, and our experience with similar soils and geologic conditions. This report should be read in conjunction with our previous report Project No. 1208-001-00, Document No. 06-0784, October 9, 2006. This previous report provides more detail on the site conditions, and geology.

HOME LAND INVESTMENTS PROJECT NO. 1208-001-01 OCTOBER 31, 2006 DOCUMENT NO. 06-0912 PAGE 2

Geotechnics Incorporated

2 SCOPE OF SERVICES The scope of services provided during this supplementary work was generally as described in our Proposal No. 06-272 dated October 16, 2006. Our scope of work included the following items:

• A subsurface exploration which included excavation of 10 exploratory test pits with a bobcat with an excavator attachment to further assess the near surface conditions. Soil samples were collected from the test pits for laboratory analysis. The test pits were logged by our field geologist. Logs of the explorations are presented in Appendix B.

• Laboratory testing of selected soil samples obtained from the test pits to assess the

pertinent physical characteristics of the on-site materials for use as aggregate. • Presentation of this report providing the results of the subsurface exploration, laboratory

testing, and our conclusions regarding the suitability of the onsite material for aggregate.

3 SITE DESCRIPTION The subject site is located approximately 500 feet northwest of the intersection between the Borrego Salton Seaway (S22) and Rockhouse Trail in Borrego Springs. The approximate site location is shown on Figure 1. The site is bordered to the west and northwest by steeply sloping east facing hills which are part of the Anza-Borrego Desert State Park. Based on topographic maps, the site generally slopes downward from these hills from an approximate elevation of 760 feet above mean sea level (MSL) in the northwest corner to an approximate elevation of 650 feet above MSL in the northeast corner and 640 feet above MSL at the bottom of drainage channels in the southwest corner. A saddle runs through the southeast corner of the site which separates drainage basins to the north and the south. An alluvial plane spreads across the landscape east and southeast of the site to the Borrego Salton Seaway. Rockhouse Trail runs across the site from the southwest to the northeast corner. Stockpiled sand materials can be found northwest of Rockhouse Trail as a result of previous mining operations. The site is vegetated with small shrubs and grasses. Numerous cobbles and boulders are exposed at the ground surface.



4 PROPOSED DEVELOPMENT It is our understanding that the site will be developed as an aggregate quarry. We understand that the quarry may extend up to approximately 120 feet below existing ground surface. Plans for the quarry development have not been provided to us. 5 GEOLOGY AND SUBSURFACE CONDITIONS The subject site is located within the Peninsular Ranges geomorphic province of southern California. This Peninsular Ranges province is characterized by rugged north-south trending mountains separated by subparallel faults, and a coastal plain of subdued landforms underlain by sedimentary formations. The approximate locations of our exploratory test pits completed for this supplementary work are shown on the Geotechnical Map, Plate 1. The boring and test pits from our previous investigation are also shown on the Geotechnical Map. The test pit logs for this supplementary work are presented in Appendix B. Generalized descriptions of the subsurface materials encountered at the site are presented below.

5.1 Alluvial Deposits The site is underlain by Quaternary age alluvial sediments. The alluvial sediments encountered in our investigation generally consist of three relatively distinct units. The contacts between these units were mapped by our field geologist and are shown on the Geotechnical Map, Plate 1. The first unit consists of light yellowish brown, fine to medium grained, poorly graded sand with silt (SP-SM), and well graded sand with silt (SW-SM). This unit covers the area of the site southeast of Rockhouse Trail. The second alluvial unit consists mostly of brown to light yellowish brown silty sand (SM) with gravel. This unit lies between Rockhouse Trail and the base of the hills along the eastern border of the site. The third unit consists mainly of brown to grayish brown silty sand (SM) with gravel as well as trace cobbles and boulders. This alluvial unit lies on the base of the hills along the eastern border of the site and appears to be the oldest of the three units. Drainage channels have been cut through this unit and well cemented layers were observed within Test Pit 2.



5.2 Groundwater Groundwater was not encountered within the test pits completed at the site.

6 LABORATORY TESTING FOR AGGREGATE EVALUATION

Selected soil samples were tested to aid in the evaluation of the aggregate. These tests should be considered an initial screening to evaluate specific aspects of the aggregate. Additional testing should be performed to evaluate the suitability of the aggregate for specific uses. The tests performed for this supplementary work included ASTM D422 (gradation with hydrometer), ASTM C127 (Density, Relative Density (Specific Gravity), and Absorption of Coarse Aggregate), ASTM C131 (Resistance to Degradation of Aggregate by Abrasion and Impact in the Los Angeles Machine), ASTM D3744 (fine and coarse durability), and ASTM D2419 (Sand Equivalent). The test results are presented in Figures C-1 through C-7 in Appendix C. Based on our laboratory test results, it appears that the aggregate tested does not meet some specifications for ASTM C131 (Resistance to Degradation of Aggregate by Abrasion and Impact in the Los Angeles Machine), or for ASTM C127 (Specific Gravity), or for ASTM D2419 (Sand Equivalent). Please note that the specifications vary with the specific use. Accordingly, the test results may meet specifications for some materials. Some of the aggregate tested does appear to meet some of the specifications. Aggregate specifications from the ASTM, Greenbook, and Caltrans are presented in the table on the following page.



AGGREGATE SPECIFICATIONS

DURABILITY ASTM D3744

(MIN.)

SPECIFIC GRAVITY

ASTM C127 (MIN.)

ABSORPTION ASTM C127 (%, MAX.)

ABRASION ASTM C131

100/500 REV. (%, MAX.)

SAND EQUIVALENT ASTM D2419

(MIN.) ASTM C33

Coarse aggregate Concrete

NA/50

GREENBOOK

Crushed Rock and Rock Dust

(Asphalt Concrete) 15/52

Screenings 12/35 Coarse Aggregate Portland Cement

Concrete 2.58 15/52

Sand Portland Cement

Concrete 70-75

Rip Rap 52 2.5 4.2 NA/45 Crushed/pulverized Miscellaneous Base

15/52 35

Emulsion Aggregate Slurry

NA/40 55

CALTRANS

Aggregate Base 35 25 Cement Treated or

Lean Concrete Base 21

Asphalt Treated Permeable Base

NA/45

(Cal. 211)

Screenings

10/40 (Cal. 211)

Type A Asphalt Concrete Base

10/45

(Cal. 211) 50

Type B Asphalt Concrete Base

NA/50

(Cal. 211) 45

Open Graded Asphalt Concrete

10/40

(Cal. 211)



7 LIMITATIONS OF INVESTIGATION This investigation was performed using the degree of care and skill ordinarily exercised, under similar circumstances, by reputable geotechnical consultants practicing in this or similar localities. No warranty, express or implied, is made as to the conclusions and professional opinions included in this report. The samples taken and used for testing and the observations made are believed representative of the project site; however, geotechnical conditions can vary significantly between field explorations. As in most projects, conditions revealed by excavation may be at variance with preliminary findings. If this occurs, the changed conditions must be evaluated by the geotechnical consultant and additional recommendations made, if warranted. This report is issued with the understanding that it is the responsibility of the owner, or of his representative, to ensure that the information and recommendations contained herein are brought to the attention of the design consultants for the project and incorporated into the plans, and the necessary steps are taken to see that the contractors carry out such recommendations in the field. Changes in the condition of a property can occur with the passage of time, whether due to natural processes or the work of man on this or adjacent properties. In addition, changes in applicable or appropriate standards of practice may occur from legislation or the broadening of knowledge. Accordingly, the findings of this report may be invalidated wholly or partially by changes outside our control. Therefore, this report is subject to review and should not be relied upon after a period of three years.

*** GEOTECHNICS INCORPORATED

Maurice Amendolagine, P.E. 62962 Paul Elliott, C.E.G. 1435 Project Engineer Senior Geologist Anthony F. Belfast, P.E. 40333 Principal Distribution: (2) Addressee (3) Warren Coalson – EnviroMINE (fax 619-284-0115)

jerryj

Text Box

6/30/08


APPENDIX A REFERENCES

American Society for Testing and Materials (2005 and 2006), ASTM Standards on Disc, Volume

04.08, Soil and Rock (I): D 420 - D 5779, Concrete and Aggregates. California Department of Transportation (2002). Standard Specifications dated July 2002. Geotechnics Incorporated, 2006. Geotechnical Investigation for Aggregate Resource Evaluation,

Bernand Quarry Site, Borrego Springs Area, San Diego County, Project No. 1208-001-00, Document No. 06-0784, dated October 9.

Geotechnics Incorporated, 2006. Proposal for Supplemental Geotechnical Investigation for

Aggregate Resource Evaluation, Bernand Quarry Site, Borrego Springs Area, San Diego County, Proposal No. 06-272, Document No. 06-0889, dated October 16.

Public Works Standards, Inc. (2006), “GREENBOOK,” Standard Specifications for Public

Works Construction, 2006 Edition.


APPENDIX B SUBSURFACE EXPLORATION

Field exploration consisted of a visual and geologic reconnaissance of the site, and completion of 10 test pits. The test pits were extended to depths of approximately 7 to 9 feet below the existing site grade. The approximate locations of the boring and test pits are shown on the Exploration Plan Map, Plate 1. Logs describing the subsurface conditions encountered in the boring and test pits are presented in Figures B-1 through B-5. The test pits were completed on October 18, 2006. The test pits were performed with a Bobcat T300 with excavator attachment. Soil samples were visually classified in the field and retained for laboratory testing. Bulk disturbed samples were collected from the test pits. Sample locations are indicated on the test pit logs with shading. The exploration locations were established in the field by judging distances from landmarks shown on the plans provided. The locations shown should not be considered more accurate than is implied by the method of measurement used. The lines designating the interface between soil units on boring logs are determined by interpolation and are therefore approximations. Note that the lines designating the interface between different soils on the logs may be abrupt or gradational. Furthermore, soil conditions at locations between the borings may be substantially different from those at the specific locations explored. It should be recognized that the passage of time can result in changes in the soil conditions reported in our logs.

Logged by: RCF Date Drilled: 10/18/2006Equipment Used: Bobcat T300 with excavator attachment Elevation: +/- 668 ft. MSL

BU

LK S

AM

PLE

LAB TESTS

Alluvium: Silty sand (SM), dark yellowish brown, fine to medium, dry.

Specific GravityWell graded sand with cobble (SW), dark yellowish brown, fine to coarse, dry, some gravel, Abrasioncobbles up to 9 inches in diameter.

Light olive brown.

Poorly graded sand with cobble (SP), olive brown, fine to medium, dry, few gravel,cobbles up to 6 inches in diameter.

Total depth: 7½ feetNo groundwater encounteredBackfilled 10/18/06


BU

LK S

AM

PLE

LAB TESTS

Alluvium: Gravelly poorly graded sand with silt (SP-SM), dark yellowish brown, fine to medium, dry, approximately 30% gravel up to 3 inches in diameter.

Specific GravityApproximately 40% gravel, some cobbles up to 6 inches in diameter. Abrasion

Coarse Durability

Total depth: 7 feetNo groundwater encounteredBackfilled 10/18/06

PROJECT NO. 1208-001-01 FIGURE B-1

8

9

LOG OF EXPLORATION TEST PIT NO. 11

DESCRIPTION

1

2

3

4

5

GEOTECHNICS INCORPORATED

DEP

TH (F

T)

1

2

8

9

10

4

6

7

5

6

7

10

3


DEP

TH (F

T)

DESCRIPTION


BU

LK S

AM

PLE

LAB TESTS

Alluvium: Gravelly poorly graded sand with silt (SP-SM), dark yellowish brown, fine to medium,dry, approximately 30 gravel, some cobbles up to 4 inches in diameter. Specific Gravity

AbrasionCoarse Durability

Poorly graded sand with gravel (SP), dark yellowish brown, fine to medium, dry.At 6 feet, approximate 6 inche layer of clayey sand.



BU

LK S

AM

PLE

LAB TESTS

Alluvium: Poorly graded sand with silt (SP-SM), olive brown, fine, dry, iron oxide staining between 1 and 5 feet.

Specific Gravity

Poorly graded sand (SP), olive brown, fine to medium, dry.



9

10


5

6

7

8

1

2

3

4

10


DEP

TH (F

T)

DESCRIPTION

6

7

8

9

2

3

4

5


DEP

TH (F

T)

DESCRIPTION

1


BU

LK S

AM

PLE

LAB TESTS

Alluvium: Silty sand with gravel (SM), dark yellowish brown, fine to coarse, dry, approximately15% gravel up to 2 inches in diameter.

Specific GravityAbrasion

Poorly graded sand with gravel (SP), dark yellowish brown, fine to medium, dry, gravel up to 2inches in diameter.

Silty sand (SM), olive brown, fine to coarse, dry, some to few gravel up to 3 inches in diameter.



BU

LK S

AM

PLE

LAB TESTS

Alluvium: Silty sand (SM), dark yellowish brown, fine to medium, dry.

Well graded sand with silt (SW-SM), light olive brown to olive brown, fine to coarse, dry, some to few gravel, few cobbles up to 6 inches in diameter. Gradation w/Hydro

Sand EquivalentFine Durability



10


6

7

8

9

2

3

4

5


DEP

TH (F

T)

DESCRIPTION

1

7

8

9

10

3

4

5

6

DEP

TH (F

T)

DESCRIPTION

1

2



BU

LK S

AM

PLE

LAB TESTS

Alluvium: Poorly graded sand (SP), olive brown, fine to medium, dry, some to few gravel.

Gradation w/HydroWell graded grand with silt and gravel (SW-SM), olive brown, fine to coarse, dry, approximately Sand Equivalent10% gravel up to 4inches in diameter. Fine Durability



BU

LK S

AM

PLE

LAB TESTS

Alluvium: Well graded sand with silt and cobble (SW-SM), dark yellowish brown, fine to coarse,dry, approximately 10% gravel and cobble up to 8 inches in diameter. Gradation w/Hydro

Sand EquivalentFine Durability

Clayey sand (SC), olive brown, fine to medium, dry, few cobble.

Silty sand (SM), olive brown, fine to medium, dry, few gravel.



9

10


5

6

7

8

1

2

3

4

9

10


DEP

TH (F

T)

DESCRIPTION

5

6

7

8

1

2

3

4


DEP

TH (F

T)

DESCRIPTION


BU

LK S

AM

PLE

LAB TESTS

Alluvium: Silty sand (SM), olive brown, fine to medium, dry.

Poorly graded sand with silt (SP-SM), olive brown, fine to medium, dry, caliche. Gradation w/HydroSand Equivalent

Some gravel up to 3 inches in diameter. Fine Durability



BU

LK S

AM

PLE

LAB TESTS

Alluvium: Silty sand (SM), olive brown, fine to medium, dry, caliche.

Poorly graded sand with silt (SP-SM), light olive brown, fine to medium, dry.

Gradation w/HydroSand EquivalentFine Durability



10


6

7

8

9

2

3

4

5


DEP

TH (F

T)

DESCRIPTION

1

7

8

9

10

3

4

5

6

DEP

TH (F

T)

DESCRIPTION

1

2



APPENDIX C LABORATORY TESTING

Selected samples of soils encountered during the investigation were tested using generally accepted testing standards. The soils selected for testing are believed to be generally representative of the materials encountered during the investigation at the site; however, variations may occur in the soils at the site, and the materials tested may not be representative of the materials encountered during construction. Laboratory testing was conducted in a manner consistent with that level of care and skill ordinarily exercised by members of the profession currently practicing under similar conditions and in the same locality. No warranty, express or implied, is made as to the correctness or serviceability of the test results or the conclusions derived from these tests. Where a specific laboratory test method has been referenced, such as ASTM or California Test, the reference applies only to the specified laboratory test method and not to associated referenced test method(s) or practices, and the test method referenced has been used only as a guidance document for the general performance of the test and not as a “Test Standard.” A brief description of the tests performed follows: Classification: Soils were classified visually according to the Unified Soil Classification System as described in ASTM D 2488. Visual classification was supplemented by laboratory testing of selected soil samples and classification in general accordance with the laboratory soil classification tests outlined in ASTM D 2487. The resultant soil classifications are shown on the boring logs in Appendix B. Specific Gravity and Absorption: The specific gravity and absorption of selected soil samples was assessed in general accordance with the laboratory procedures outlined in ASTM test method C127. Bulk samples were combined from selected intervals to perform the tests. The results are summarized in Figure C-1. LA Abrasion: The degradation of selected soil samples was assessed in general accordance with the laboratory procedures outlined in ASTM test method C131. The results are summarized in Figure C-1. Durability: The fine and coarse durability of selected soil samples was assessed in general accordance with the laboratory procedures outlined in ASTM test method D3744. The results are summarized in Figure C-2.


APPENDIX C

LABORATORY TESTING (Continued)

Sand Equivalent: The sand equivalent of selected soil samples was assessed in general accordance with the laboratory procedures outlined in ASTM test method D2419. The results are summarized in Figure C-2. Particle Size Analysis: Particle size analyses were performed on selected soil samples in general accordance with the laboratory procedures outlined in ASTM D 422. The grain size distribution was used to estimate presumptive soil strength parameters and foundation design criteria. The test results are presented in Figures C-3 through C-7.

Project No. 1208-001-01 Document No. 06-0912 TEST RESULTS FIGURE C-1

LOS ANGELES (L.A.) ABRASION TEST (ASTM C131)

SAMPLE NO. SAMPLE DESCRIPTION TEST GRADING

WEAR 100 Rev

(%)

WEAR 500 Rev

(%)

TP-11 at 2-4 ft. SW BB (½-¾ in.) 14.1 46.5

TP-12 at 4-6 ft. SP-SM AA (1½-⅜ in.) 14 41.5

TP-13 at 1-3 ft. SP-SM AA (1½-⅜ in.) 13.2 42.5

TP-15 at 2-4 ft. SM AA (1½-⅜ in.) 14.6 44

SPECIFIC GRAVITY AND ABSORPTION (COARSE) (ASTM C127)

SAMPLE NO. SAMPLE DESCRIPTION

OVE

N D

RY

BU

LK S

PEC

IFIC

G

RA

VITY

SATU

RA

TED

SU

RFA

CE

DR

Y B

ULK

SPE

CIF

IC

GR

AVI

TY

APP

AR

ENT

SPEC

IFIC

G

RA

VITY

AB

SOR

PTIO

N

(%)

TP-11 at 2-4 ft. SW 2.601 2.636 2.696 1.348

TP-12 at 4-6 ft. SP-SM 2.607 2.654 2.735 1.794

TP-13 at 1-3 ft. SP-SM 2.646 2.681 2.741 1.310

TP-14 at 2-5 ft. SP-SM 2.358 2.470 2.654 4.737 (caliche)

TP-15 at 2-4 ft. SM 2.542 2.6 2.699 2.282

Project No. 1208-001-01 Document No. 06-0912 TEST RESULTS FIGURE C-2

DURABILITY INDEX

(ASTM D3744)

SAMPLE NO. SAMPLE DESCRIPTION COARSE DURABILITY

TP-12 at 4-6 ft. SP-SM 76


DURABILITY INDEX (ASTM D3744)

SAMPLE NO. SAMPLE DESCRIPTION FINE DURABILITY

TP-16 at 4-6 ft. SW-SM 31





SAND EQUIVALENT (ASTM D2419)

SAMPLE NO. SAMPLE DESCRIPTION SAND EQUIVALENT






UNIFIED SOIL CLASSIFICATION: SW-SM ATTERBERG LIMITSEXPLORATION NUMBER: TP-16 LIQUID LIMIT: N/T

SAMPLE DEPTH: 4'-6' DESCRIPTION: Well Graded Sand with Silt PLASTIC LIMIT: N/TPLASTICITY INDEX: N/T

Project No. 1208-001-01

SOIL CLASSIFICATION Document No. 06-0912

FIGURE C-3

SAMPLE

0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100

Grain Size in Millimeters

U.S. Standard Sieve Sizes

Perc

ent F

iner

by

Wei

ght

SILT AND CLAYCOARSE FINE

GRAVEL SAND

COARSE FINEMEDIUM

3" 1-1/2" 3/4" 3/8" #4 #8 #16 #30 #50 #100 #200 Hydrometer


SAMPLE DEPTH: 5'-7' DESCRIPTION: Well Graded Sand with Silt and Gravel PLASTIC LIMIT: N/TPLASTICITY INDEX: N/T

Project No. 1208-001-01


FIGURE C-4

SAMPLE

0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100



Perc

ent F

iner

by

Wei

ght


GRAVEL SAND

COARSE FINEMEDIUM

3" 1-1/2" 3/4" 3/8" #4 #8 #16 #30 #50 #100 #200 Hydrometer


SAMPLE DEPTH: 1'-2' DESCRIPTION: Well Graded Sand with Silt PLASTIC LIMIT: N/TPLASTICITY INDEX: N/T

Project No. 1208-001-01


FIGURE C-5

SAMPLE

0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100



Perc

ent F

iner

by

Wei

ght


GRAVEL SAND

COARSE FINEMEDIUM

3" 1-1/2" 3/4" 3/8" #4 #8 #16 #30 #50 #100 #200 Hydrometer

UNIFIED SOIL CLASSIFICATION: SP-SM ATTERBERG LIMITSEXPLORATION NUMBER: TP-19 LIQUID LIMIT: N/T

SAMPLE DEPTH: 4'-6' DESCRIPTION: Poorly Graded Sand with Silt PLASTIC LIMIT: N/TPLASTICITY INDEX: N/T

Project No. 1208-001-01


FIGURE C-6

SAMPLE

0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100



Perc

ent F

iner

by

Wei

ght


GRAVEL SAND

COARSE FINEMEDIUM

3" 1-1/2" 3/4" 3/8" #4 #8 #16 #30 #50 #100 #200 Hydrometer

UNIFIED SOIL CLASSIFICATION: SP-SM ATTERBERG LIMITSEXPLORATION NUMBER: TP-20 LIQUID LIMIT: N/T

SAMPLE DEPTH: 5'-7' DESCRIPTION: Poorly Graded Sand with Silt PLASTIC LIMIT: N/TPLASTICITY INDEX: N/T

Project No. 1208-001-01


FIGURE C-7

SAMPLE

0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110100



Perc

ent F

iner

by

Wei

ght


GRAVEL SAND

COARSE FINEMEDIUM

3" 1-1/2" 3/4" 3/8" #4 #8 #16 #30 #50 #100 #200 Hydrometer

SCALE: 1" = 200'

Explanation

PLATE 1

Home Land Investments

Bernand Quarry Site

GEOTECHNICAL MAP

IncorporatedGeotechnics Project No.1208-001-01

Document No. 06-0912

Reference: BURNAND_CONTOURS_5 and 10ft_CLIPs.dwg, provided by Enviromine

640

650

660

660

670

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690

700

700

710

720

730

740

750

660

650

650

650

660

660

670

670

670

680

690

690

700

700

710

720

730

660

TP-1

TP-2

TP-3

TP-4

TP-5

TP-6

TP-7

TP-8

TP-9

TP-10

B-1

Qal1

Qal2

Qal2

Qoal

Qoal

Qoal

TP-12

TP-13

TP-15

TP-14

TP-16

TP-11

TP-18

TP-19TP-20

TP-17

Approximate location of test pit

TP-10

Approximate location of boring B-1

Alluvium, poorly graded sandQal1

Alluvium, silty sand with gravelQal2

Older alluvium, silty sand with gravelQoal

Approximate location of geologic contact

Documents

SUPPLEMENTARY INVESTIGATION AND LABORATORY … SPRINGS...• Presentation of this report providing the results of the subsurface exploration, laboratory testing, and our conclusions